Mine works great, I would give it a grade of **8**.
But you really need to change the water/solution every time. I mix it up a gallon of distilled water at a time and that sames a lot of time over measuring and mixing just one cleaning batch at a time.
It's a lot more expensive to use than a tumbler with corncob or walnut media. The solution doesn't grow on trees. I've researched this a LOT and I can't find anyone who is happy with any kind of home brew they've worked up, including Simple Green, the smell of which makes me yak anyway.